First, let me start by saying I am a first time ATV owner (just purchased a new 2003 Forman 450 ES - With winch, tax, title, license, and ramp for a hair under 6K!), and I pick it up on 11/11. I did alot of research and Honda's just seem to be the best all around ATV out there.

Anyway, I live in MN so the Forman comes with the standard Carborator Jet of 0-3000 feet (I believe). Has anyone taken there ATV out to the Mountains (I go to Colorado every summer)? Is there a need to rejet the carborators? I called two local dealers one says to rejet, and the other one says most people do not. Has anyone not rejetted when riding in the mountains? Just wondering. BTY, I will be ridding at about 9000 ft and up.

Thanks in advance for the info.

 

We live in a valley that is 4200 ft at the floor. Just about every place we ride from here is up. The dealer we bought our ATV's from replaced the #130 jet to a #125 in our Rancher as part of the predelivery. It was included in the purchase price. The #158 jet in our Rubicon was replaced with a #150 at time of it's predelivery. Both of these ATV's run great all the time but we have never run them at 3000 ft. They run very respectable at 13,500 ft. and it just gets better as you drop in elevation.

Your ATV will definitely run a lot richer in the higher altitude. It may have a tendency to backfire when decelerating and even stall when you let off the throttle. It would also have more power with a smaller jet than one for sea level in the higher elevation.

From sea level to 9000 ft, you will loose between 20 and 25% of the power. It would run better re-jetted. You should re-jet when get home too. Get a quote, your call.

 

Specta;

Thanks for the insight. I was thinking of this prior to buying the ATV, so I had them include rejetting (for the first 3 years) as part of the package. I was not sure if it was needed or not, but I wanted to make sure I was covered. I think it will be something that I will do each year. Thanks again for the info.

 

www.thunderproducts.com

I live in the valley at about 1,200', and my bikes are jetted for sea level. On any day I can be riding at BELOW sea level in the low desert, or at 4,000' in the high desert, or at 10,000' in the mountains. Tough to rejet for all those locations, huh! I install two TPI Valves in my airbox lids. As I ascend in altitude, I open up the valves to compensate for the thinner air (and close them as I descend). It is the slick and easy solution to the problem, and works very well! Above 10,000', I pull the airbox lid completely off, and the bike rips.

On the other hand, if you are just making a once a year trip, changing out a main jet (once a year!) isn't that big a deal. Trouble is, if you didn't get the jet just right, what are you going to do? With the TPI, I just open or close the valve a little more and I have instant compensation, anywhere I go. I have better performanc than others who specifically rejet for altitude.